Inflammation has pleiotropic effects on carcinogenesis and tumor progression. Signaling through the adaptor protein MyD88 promotes carcinogenesis in several chemically induced cancer models. Interestingly, we observed a protective role for MyD88 in the development of AOM/DSS colitis-associated cancer. The inability of Myd88-/- mice to heal ulcers generated upon injury creates an inflammatory environment that increases the frequency of mutations and results in a dramatic increase in adenoma formation and cancer progression. Susceptibility to colitis development and enhanced polyp formation were also observed in Il18-/- mice upon AOM/DSS treatment, suggesting that the phenotype of MyD88 knockouts is in part due to their inability to signal through the IL-18 receptor. This study revealed a previously unknown level of complexity surrounding MyD88 activities downstream of different receptors that differentially impact tissue homeostasis and carcinogenesis.
MyD88-mediated signaling prevents development of adenocarcinomas of the colon: role of interleukin 18.
Specimen part, Disease, Disease stage
View SamplesMuscles organise a pseudo-crystalline array of actin, myosin and titin filaments to build force-producing sarcomeres. To study how sarcomeres are built, we performed mRNA-sequencing of developing Drosophila flight muscles and identified 40 distinct expression profile clusters. Strikingly, two clusters are strongly enriched for sarcomeric components. Temporal gene expression together with detailed morphological analysis enabled us to define two distinct phases of sarcomere development, both of which require the transcriptional regulator Spalt major. During the first sarcomere formation phase, 2.0 µm long immature sarcomeres assemble myofibrils that spontaneously contract. In the second sarcomere maturation phase, sarcomeres grow to their final 3.2 µm length and 1.5 µm diameter and acquire stretch-sensitivity. Interestingly, the final number of myofibrils per flight muscle fiber is determined at the onset of the first phase and remains constant. Together, this defines a biphasic mode of sarcomere and myofibril morphogenesis – a new concept which may also apply to vertebrate muscle or heart development. Overall design: Part I: An 8-point timecourse of wild-type flight muscle development in Drosophila melanogaster was analyzed with duplicates/triplicates for each timepoint Part II: A Mef2-Gal4 x salmIR timecourse in duplicate at 4 timepoints was compared to wild-type flight muscle
A transcriptomics resource reveals a transcriptional transition during ordered sarcomere morphogenesis in flight muscle.
Specimen part, Subject
View SamplesTumor cells exhibit aberrant metabolism characterized by high glycolysis even in the presence of oxygen. This metabolic reprogramming, known as the Warburg effect, provides tumor cells with the substrates and redox potential required for the generation of biomass. Here, we show that the mitochondrial NAD-dependent deacetylase SIRT3 is a crucial regulator of the Warburg effect. SIRT3 loss promotes a metabolic profile consistent with high glycolysis required for anabolic processes in vivo and in vitro. Mechanistically, SIRT3 mediates metabolic reprogramming independently of mitochondrial oxidative metabolism and through HIF1a, a transcription factor that controls expression of key glycolytic enzymes. SIRT3 loss increases reactive oxygen species production, resulting in enhanced HIF1a stabilization. Strikingly, SIRT3 is deleted in 40% of human breast cancers, and its loss correlates with the upregulation of HIF1a target genes. Finally, we find that SIRT3 overexpression directly represses the Warburg effect in breast cancer cells. In sum, we identify SIRT3 as a regulator of HIF1a and a suppressor of the Warburg effect.
SIRT3 opposes reprogramming of cancer cell metabolism through HIF1α destabilization.
Specimen part
View SamplesTGF is one of most intensively studied regulators of extracellular matrix formation, and has been implicated in the development of pulmonary fibrosis in different models. However, little is know about the role of miRNAs in TGF mediated fibrogenic gene regulation. By using miRNA qRT-PCR array, we have identified miRNAs whose expression are regulated by TGF in IMR-90 cells. Among those down-regulated miRNAs are miR-29 family members. Knockdown miR-29 in IMR-90 cells results in up-regulation of a large number of extracellular matrix and fibrogenic genes including family members of collagen, laminin, integrin, ADAM and MMP, many of them are predicted or confirmed miR-29 targets. Hierarchichal clustering analysis of mRNA array data revealed that many extracellular matrix and fibrogenic genes up-regulated by TGF in IMR-90 cells, are also up-regulated in miR-29 KD cells. Moreover, the similar set of extracellular matrix and fibrogenic genes is also significantly up-regulated in bleomycin treated mouse lungs. Together, our data strongly suggest that downstream of the TGF, miR-29 is a master modulator of genes involved in extracellular matrix formation and might play a significant role in pulmonary fibrosis.
miR-29 is a major regulator of genes associated with pulmonary fibrosis.
Specimen part, Cell line
View SamplesGW182 (Tnrc6a) is a key component of RISC (miRNA-Induced Silencing Complex) that plays a critical role in miRNA-mediated gene silencing. Here, we show that GW182 is expressed in the yolk sac endoderm, and that gene-trap disruption of GW182 leads to growth arrest of yolk sac endoderm, impaired hematopoiesis and embryonic lethality.
Trinucleotide repeat containing 6a (Tnrc6a)-mediated microRNA function is required for development of yolk sac endoderm.
Specimen part
View SamplesMulticiliated cells are crucial for fluid and ion transport in epithelia of a variety of organs and their impaired development and function are seen in human diseases affecting the brain, respiratory, and reproductive tracts. Multiciliogenesis requires activation of a specialized transcription program coupled to complex cytoplasmic events that lead to large-scale centriole amplification to generate multicilia. Yet, it remains unclear how these events are coordinated to initiate multiciliogenesis in epithelial progenitors. Here we identify an unsuspected mechanism orchestrated by the transcription factor E2f4 essential to integrate these processes. We show that after inducing a transcriptional program of centriole biogenesis, E2f4 translocates to the cytoplasm to become a core component of structures classically identified as fibrous granules (FG), acting as organizing centers for deuterosome assembly and centriole amplification. Remarkably, loss of cytoplasmic E2f4 prevents FG aggregation, deuterosome assembly and multicilia formation even when E2f4s transcriptional function is preserved. Moreover, in E2f4-deficient cells multiciliogenesis is rescued only if both nuclear and cytoplasmic E2f4 activities are restored. Thus, E2f4 integrates previously unrelated nuclear and cytoplasmic events of the multiciliated cell program.
Cytoplasmic E2f4 forms organizing centres for initiation of centriole amplification during multiciliogenesis.
Specimen part
View SamplesSalmonella enterica is a Gram-negative bacterium that causes gastroenteritis, bacteremia and typhoid fever in several animal species including humans. Its virulence is greatly dependent on two type III secretion systems (T3SSs), encoded in pathogenicity islands 1 (SPI1) and 2 (SPI2), respectively. These systems translocate proteins called effectors into eukaryotic host cell. Effectors interfere with certain host signal transduction pathways to allow the internalization of pathogens and their survival and proliferation inside vacuoles. SteA is one of the few Salmonella effectors that are substrates of both T3SSs. Nothing is known about the function of this protein inside the host cells. Here, we used gene arrays and bioinformatics analysis to study the genetic response of human epithelial cells to SteA. We found that constitutive synthesis of SteA in epithelial cells leads to induction of genes related to extracellular matrix organization and regulation of cell proliferation and serine/threonine kinase signaling pathways. SteA also represses genes related to immune processes and regulation of purine nucleotide synthesis and pathway-restricted SMAD protein phosphorylation. Consisted with this analysis a cell biology approach revealed that epithelial cells expressing steA show altered cell morphology, reduction of cytotoxicity, cell-cell adhesion and migration capability, and increase in endocytosis.
Global impact of Salmonella type III secretion effector SteA on host cells.
Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
PI3K inhibition synergizes with glucocorticoids but antagonizes with methotrexate in T-cell acute lymphoblastic leukemia.
Sex, Age, Specimen part, Cell line
View SamplesThe PI3K pathway is frequently hyperactivated in primary T-cell acute lymphoblastic leukemia (T-ALL) cells. Activation of the PI3K pathway has been suggested as one mechanism of glucocorticoid resistance in T-ALL, and patients harboring mutations in the PI3K negative regulator PTEN may be at increased risk of induction failure and relapse. In this study, we identified Myc as an important downstream integrator of PI3K pathway activity in T-ALL and we provide data supportive of an association of higher PI3K activity with glucocorticoid resistance and worse clinical outcome. The PI3K inhibitor AS605240 showed anti-leukemic activity and strong synergism with glucocorticoids both in vitro and in a NOD/SCID xenograft model of T-ALL. In contrast, PI3K inhibition showed antagonism with methotrexate and daunorubicin, drugs that preferentially target dividing cells. This antagonistic interaction, however, could be circumvented by the use of correct drug scheduling schemes. Our data indicate the potential benefits and difficulties for the incorporation of PI3K inhibitors in T-ALL therapy.
PI3K inhibition synergizes with glucocorticoids but antagonizes with methotrexate in T-cell acute lymphoblastic leukemia.
Sex, Age, Specimen part
View SamplesThe PI3K pathway is frequently hyperactivated in primary T-cell acute lymphoblastic leukemia (T-ALL) cells. Activation of the PI3K pathway has been suggested as one mechanism of glucocorticoid resistance in T-ALL, and patients harboring mutations in the PI3K negative regulator PTEN may be at increased risk of induction failure and relapse. In this study, we identified Myc as an important downstream integrator of PI3K pathway activity in T-ALL and we provide data supportive of an association of higher PI3K activity with glucocorticoid resistance and worse clinical outcome. The PI3K inhibitor AS605240 showed anti-leukemic activity and strong synergism with glucocorticoids both in vitro and in a NOD/SCID xenograft model of T-ALL. In contrast, PI3K inhibition showed antagonism with methotrexate and daunorubicin, drugs that preferentially target dividing cells. This antagonistic interaction, however, could be circumvented by the use of correct drug scheduling schemes. Our data indicate the potential benefits and difficulties for the incorporation of PI3K inhibitors in T-ALL therapy.
PI3K inhibition synergizes with glucocorticoids but antagonizes with methotrexate in T-cell acute lymphoblastic leukemia.
Sex, Specimen part
View Samples